This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This project investigates sex differences in the social, emotional, cognitive and neuroendocrine consequences of neonatal and post-pubertal amygdalectomy in rhesus monkeys living in complex semi-natural social groups. Unlike the severely socially restricted conditions of previous studies, our large monkey groups have multiple matrilines and all age and sex classes allowing investigating amygdala function under social conditions it is likely designed to deal with. This project tracks the development of these systems and relates changes in juvenile function to the pubertal transition and adult social behavior. We have now successfully created forty-one monkey subjects in two annual cohorts, including 9 male and 8 female neonatally amygdalectomized subjects, with the other 24 subjects serving as juvenile controls. Eight male and 8 female controls will be amygdalectomized 1 year post-pubertally to allow direct comparison of the effects of neonatal and adult amygdalectomy Neonatal gonadal function, anxiety, fear, and maternal attachment are in the process of being assessed along with extensive observations of social interactions in the subjects'natal group during the first four years of life. At 2 yr, continuously available computer kiosks will be used to assess object and spatial memory span and object discrimination. Starting at 1.25yr females have been intensely sampled to assess pubertal timing as well as pubertal changes in social and sexual behavior. Surprisingly, the one neonatally amygdalectomized female in our first cohort (the rest of the amygdalectomized females were created in the second cohort completed this year) went through menarche at 1.5years, a full year earlier than any control female in our colony has gone through puberty. We have continued weekly focal observations of behavior, neonatal imitation, and LabTab performance has been collected on these subjects. Sample sizes will are now sufficient for data analysis, which is currently under way.